Pressure-retaining valve.



No. 747,655. l PATENTED DEG. 2z, 1903.v

P. P. -SKEPFINGTON PRESSURE. RBTAINING VALVE.

l APPLICATION FILED AUG. 3, 1903. N0 MODEL.

UNITED STATES FRANCIS P. sKEFFINGrIoN,` oF sPoKANE, WASHINGTON.

PRESSU RE-v-RETAINING VALVEL.`

Patented December 22, 190l3.l

'PATENTy OFFICE.

SPECIFICATION forming part of Letters Patent No. 747,656, dated December 22, 1,903.`

`Application iled August 3, 1903.

.To all whom it may concern:

Be it known that I, FRANCIS P. SKEFFING- TON, a citizen of the United States, residing at Spokane, in the county of Spokane and State of Washington, have invented new and useful Improvements in Pressure Retaining Valves, of which the following is a specification.

This invention relates particularly to pressure-retainers used in connection with air#y brakes to retain the full pressure on the brakes until the auxiliary reservoir is recharged.

The object of the invention is to produce an improved valve for the purpose indicated and also to produce a combined pressure-re-v taining and bleed valve. A

Further advantages ofV operation andzconstruction will be apparent-from the following description and from the accompanying drawings, in which- Y Figure l is an elevation of the auxiliary reservoir of a freight-car brake with my valve applied thereto. Fig. 2 is va'verticalsection through the valve on the line 2 2 of- Fig. l. Fig. 3 is a horizontal section on.theline 3 3 of Fig. 2; and Fig. 4 is a section'si'milar. to Fig.' 3, showing the valve in a dierent position.

The invention is characterized particularly by the combinationof a pressure-retaining valve and a bleed-Valve in one casing and so arranged that when the bleed-valve is operated the pressure is released from both the auxiliary reservoir and the chamber and valve controlling the triple-,valveexhaust or brakerelease.

Referring specifically to the drawings, C indicates a casting containing the valves, having a cylindrical bore producing two chambers (indicated at B and R) on opposite sides of the piston X2 of apiston-valve, which is slidable in the bore. At substantially a right angle to the cylinder just mentioned the casting is bored to produce chambers A' and A2, which are connected by a port z. The chamber A communicates With the auxiliary reservoir through a screw-plug L and contains a valve a', normally seated over the port z. The stem of the valve projects partly through the port, as indicated at a2.' This chamber A is in communication with the chamber B through the oblique port B2, which opens into the chamber B beyond the piston Serial No. 168.055. (No model.)

X2.- The end of the chamber B is closed bya screw-cap A, which has a central stem ot,

,casing M, which is screwed therein and con- .tains a valve mz, the stem of which extends upwardly through the discharge-port to contact with the bleed-cock leverv N. On the other side of the valve 'm the valve-stem extends downwardly into the port .a and almost in contact with the stem a2 of the valve a'. The chamber A2 also communicates with the chamber R through a comparatively wide opening or port produced in the side of the cylinder, as indicated at y. At Y is a port leading from thecylinder to the atmosphere. The rod of the piston X2 carries also a piston `X",ftti'ng.the cylinder and so positioned that it will cover or uncover the port Y and connect Athe port y `and the chamber A2 therewith.

The stem of the piston-valve is continued or projects beyond the piston X', as indicated ats, into the bore of the adjusting-nut D, and between said nut `and the piston X' is a spring S, coiledaround said stem. The pressure of this spring is adjustable by means f the nut D, which works in the inside nut B in the end of the cylinder. The chamber A2 is in communication with the triple-valve exhaust or brake-release port through the pipe X.

In operation the spring S is set at the desired tension, according to the pressure in the auxiliary reservoir, so that when said pressure is below the normal the spring will force the piston-valve to the position shown in Fig; 3, where the exhaust-port Y is cut off from the chamber A2 and pipe X, and consequently the exhaust from the triple valve is prevented, whereby the brakes are held set until the auxiliary reservoir is recharged to the normal pressure. Then, said pressure passing into the chamber B', it forces the pistonvalve to the position shown in Fig. 4., uncovering the port Y and allowing the exhaust from the triple valve to dow through the pipe X, chamber A2, and ports y and Y. There is thus no exhaust from the triple valve until IOO the pressure in the auxiliary reservoir exceeds the tension of the spring S, which, as said before, is set at normal pressure-say sixty-tive pounds.

The action of the bleed-cock is as follows: When the lever is pulled, it forces down and opens the valve m, the stern of which presses against the stem a? and opens in turn the valve a.' or port a. reservoir and also through the port B2 bleeds the chamber B', triple valve, and brake-cylinder, and thereby releases the brakesafter all the air is drawn 0E. This is particularly serviceable in preparing cars for switching when the air-brakes are not in use.

By the construction shown a combined retaining and bleed-valve is produced having manifest advantages of simplicity and eectiveness.

What I claim as new, and desire to secure by Letters Patent, is-

1. In an air-brake system, the combination with an automatic pressure-retaining valve connected to the auxiliary reservoir and the triple-valve exhaust, of a bleed-valve controlling and in communication with the pressure-retaining valve and the auxiliary reservoir.

2. In an air-brake system, the combination with a pressure-retaining valve receiving on opposite sides the pressure from the auxiliary reservoir and a spring, and controlling the tri ple-valve exhaust, of a bleed-valve controlling theexhaust from the auxiliary reservoir, the pressure-retaining valve and the triple valve.

3. In an air-brake system, the combination with a pressure-retaining valve controlling the exhaust from the triple valve, of a bleed valve controlling the pressure retaining valve.

4. In an air-brake system, the combination with the auxiliary reservoir and triple valve, of a bleed-valve controlling exhaust from the reservoir and from the triple valve.

This bleeds the auxiliary 5. In anair-brake system, the combination with a pressure-retaining valve controlling the exhaust from the triple valve and controlled by the pressure in the auxiliary reservoir, of a bleed-cock in communication with the triple-valve exhaust, whereby said exhaust may be directly controlled.

6. In an air-brake system, the combination with an auxiliary reservoir, triple valve, and pressure-retaining valve, of a bleed-cock having two valves, one of which controls the air escape from the auxiliary reservoir retaining-valve, and the other the air escape from the triple valve.

7. In an air-brake system, a combined pressure-retainingand bleed valve, comprisingla cylinder having an exhaust-port to the atmosphere, a spring-pressed piston-valve in the cylinder adapted to cover or uncover the port, a passage from the auxiliary reservoir to one side of the piston, apassage from the triple-valve exhaust to the other side of the piston, a port connecting said passages, and a bleed-valve controlling said port.

8. In an air-brake system, the combination with a triple valve, having two exhaustvents, of an automatic pressure-retaining valve controlling one vent, and a bleed-cock controlling the other. y

9. The combination with an auxiliary-reservoir and triple valve, of a cylinder having an atmospheric vent at one end, a passage at the other end to the auxiliary reservoir, and an intermediate passage to the triple-valve exhaust, a spring-pressed piston-valve slidable in the cylinder, controlling the atmospheric vent, aport between said passages, and a bleed-valve controlling said port.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRANCIS P. SKEFFINGTON.

Witnesses:

HARRY C. Pncx, MAURICE P. WILKINs. 

